THIS invention relates to excavation buckets, and more specifically to a lip for an excavation bucket.
Excavation buckets such as dragline buckets generally have a lip welded to the front of the bucket for supporting a plurality of ground-engaging tools. These lips are usually formed from a single, rolled steel or cast steel plate with a straight front edge, and include a plurality of nosepiece castings which are fixed to the lip so as to project from the front edge of the lip. Ground-engaging tools are mechanically attached to the nosepieces, typically by means of adaptor castings.
The castings tend to be relatively heavy and consequently contribute significantly to the overall mass of the lip. Since the total mass of a loaded dragline bucket is limited by the dragline rated suspended load (RSL), it is desirable to reduce the mass of the bucket so as to allow for an increase in the bucket load and hence the productivity of the dragline.
A further disadvantage associated with conventional lips for dragline buckets is that the nosepiece castings have to be welded to the lip with transverse welds that extend across the upper and lower surfaces of the lip, and these welds reduce the fatigue strength of the lip.